[PATCH] crypto: sig - Fix verify call

[Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>]

The dst SG list needs to be set to NULL for verify calls.  Do
this as otherwise the underlying algorithm may fail.

Furthermore the digest needs to be copied just like the source.

Fixes: 6cb8815f41a9 ("crypto: sig - Add interface for sign/verify")
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>

diff --git a/crypto/akcipher.c b/crypto/akcipher.c
index 152cfba1346c..0eb8f78751d5 100644
--- a/crypto/akcipher.c
+++ b/crypto/akcipher.c
@@ -192,12 +192,17 @@ EXPORT_SYMBOL_GPL(akcipher_register_instance);
 int crypto_akcipher_sync_prep(struct crypto_akcipher_sync_data *data)
 {
 	unsigned int reqsize = crypto_akcipher_reqsize(data->tfm);
-	unsigned int mlen = max(data->slen, data->dlen);
 	struct akcipher_request *req;
 	struct scatterlist *sg;
+	unsigned int mlen;
 	unsigned int len;
 	u8 *buf;
 
+	if (data->dst)
+		mlen = max(data->slen, data->dlen);
+	else
+		mlen = data->slen + data->dlen;
+
 	len = sizeof(*req) + reqsize + mlen;
 	if (len < mlen)
 		return -EOVERFLOW;
@@ -212,9 +217,10 @@ int crypto_akcipher_sync_prep(struct crypto_akcipher_sync_data *data)
 	data->buf = buf;
 	memcpy(buf, data->src, data->slen);
 
-	sg = data->sg;
+	sg = &data->sg;
 	sg_init_one(sg, buf, mlen);
-	akcipher_request_set_crypt(req, sg, sg, data->slen, data->dlen);
+	akcipher_request_set_crypt(req, sg, data->dst ? sg : NULL,
+				   data->slen, data->dlen);
 
 	crypto_init_wait(&data->cwait);
 	akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
diff --git a/crypto/internal.h b/crypto/internal.h
index e3cf5a658d51..63e59240d5fb 100644
--- a/crypto/internal.h
+++ b/crypto/internal.h
@@ -44,7 +44,7 @@ struct crypto_akcipher_sync_data {
 
 	struct akcipher_request *req;
 	struct crypto_wait cwait;
-	struct scatterlist sg[2];
+	struct scatterlist sg;
 	u8 *buf;
 };
 
diff --git a/crypto/sig.c b/crypto/sig.c
index d812555c88af..b48c18ec65cd 100644
--- a/crypto/sig.c
+++ b/crypto/sig.c
@@ -128,9 +128,7 @@ int crypto_sig_verify(struct crypto_sig *tfm,
 	if (err)
 		return err;
 
-	sg_init_table(data.sg, 2);
-	sg_set_buf(&data.sg[0], src, slen);
-	sg_set_buf(&data.sg[1], digest, dlen);
+	memcpy(data.buf + slen, digest, dlen);
 
 	return crypto_akcipher_sync_post(&data,
 					 crypto_akcipher_verify(data.req));
-- 
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt